Consider this code:

#include <ranges>
#include <memory>
#include <list>
#include <vector>

template <typename T>
struct A
{
    std::vector<T> v;

    template <typename U>
    A(U &&input) : v(std::from_range, std::forward<U>(input)) {}
};

int main()
{
    A<std::unique_ptr<int>> a(std::list{std::unique_ptr<int>{}});
}

It doesn’t compile, as std::from_range tries to copy the elements instead of moving them. run on gcc.godbolt.org

What is the correct and idiomatic solution here? I want it to automatically move the elements if source range is an rvalue and owns the elements.

I know std::views::as_rvalue exists, but deciding when to apply it requires a lengthy condition:

• The input range must be an rvalue.
• It must own the elements (std::borrowed_range<U &> == false, I assume?)

Sure, I can write out this condition manually, but naively hoped that Ranges has a built-in solution to this problem.